When Dry Rot Strikes: The Art of Tire Maintenance

An expert weighs in on how to keep you and your wheels alive

When it comes to car ownership, the amount of knowledge needed to be a savvy buyer is almost an impossible feat to conquer, let alone understanding the mechanical workings of a vehicle. It always struck me as odd that people will educate themselves extensively on things like whether or not their lettuce is fair trade or organic, conspiracy theories, and what juice cleanse will help them free their liver of toxins. But they won[t take the time to learn about the second largest purchase almost every American makes. I myself prefer my lettuce dirty—and my liver even dirtier—but I do have an unnecessary amount knowledge on the inner workings of the modern automobile.

I have spent the better part of the last decade working at two of the largest car manufacturers in the world, as well the largest tire distributor in the United States. I now own my own business related to the automotive field. During my tenure at those companies prior, though, nothing was drilled harder into my head than tires and tire care. One might call me a “tire expert.” That’s right, tires—those little rubber things that keep you stuck on the road. I’ve endured countless hours learning about exactly how the rubber compounds (known as silica) are made, what causes treadwear, and even decoding all those numbers on the side of the tire that most people never even notice. Who taught me this. you ask? No one that special; only reps directly from Michelin, BFGoodrich, Goodyear, Hankook, Bridgestone, and Yokohama.

Tires are often the most overlooked and ignored part on a car. I get that they are expensive, and clearly not that important, right? Its not like they’re your brakes.

Wrong!

Tires are the possibly the most important safety feature on any vehicle, even surpassing the brakes. They are the only part of your car that actually makes contact with the road’s surface. Poor tire maintenance can have a negative effect of your vehicles, stopping distance, handling, and traction while driving in stormy weather. So every time that nice young service person recommends you replace your tires, I would advise you don’t just blow him off as a guy trying to make some commission. He may actually be right.

But no worries, that is why I’m here. To educate my fellow Proud Boys in proper tire care, maintenance, and potential warning signs that something catastrophic may be around the bend. (Road pun?)

First we must understand the anatomy of a tire and how they are categorized. Every modern tire is comprised of a series of strategically placed steel belts, surrounded by a rubber compound mixed with sand (forming silica) which is poured in a mold forming different tread patterns. The tread patch is the part of the tire that makes contact with the road, the sidewall is the part that goes from the tread patch to the bead, and the bead is the hardened part of the tires that goes onto your rim creating an airtight seal.

Tires options are pretty much endless, but are categorized by a few different things. Tire
size, traction rating, temperature rating, treadwear rating, and speed rating.
Tire size—shown as a sequence of three numbers (205/55/16):
The 205 refers the tread patch (205mm wide).
The 55 is an aspect-ratio for the sidewall, meaning the side is 55% of the total width of the tire’s tread patch (smaller numbers means better handling by stiffer rides).
The 16 is the rim size… simple enough.

The traction and temperature ratings are determined by the department of transportation and based on bench mark tire for each manufacturer (in essence the least important rating of a tire but one that still shouldn’t be ignored). Treadwear refers to how hard the tread and rubber compound is, resulting in either increased or decreased tire wear. The speed rating normal at the end of a tire size (205/55/16H) refers to what the maximum speed the tire is rated for. In this case H is good for around 130 mph before it starts to lose its shape and structural integrity The speed rating will also effect the stopping distance of a vehicle as a lower speed rating will allow more flex in the tire, thus decreasing stopping distance.

While all of this is incredibly simplified, you get the idea. Always select the correct tires for your vehicle as recommended by your vehicle manufacturer. Which leads
to the most important part of tire ownership: maintenance, which includes:

TIRE PRESSURE

– Recommended tire pressures will be listed on the driver’s doorjamb (NOT ON
THE TIRE).
– Improper tire pressures (underinflated/overinflated) will cause uneven wear on
both outer edges or only the center of the tire, as well a rough ride, decreases
steering and handing capabilities, and possible overheating of the rubber (if
underinflated), causing a blowout.
– Remember that for every 10 degrees the outside temperature changes (up or
down) the tires pressure will change, as the air density in the tire is affected.
– MORAL: CHECK YOUR TIRE PRESSURE ONCE A MONTH

ROTATION

– Rotate your tires front to back every 5-10,000 miles.
– Cross-rotate only if you have different tires sizes on the front and rear.
– Lack of rotation will cause the front two tires to wear faster than the rear, seeing as your front tires also steer and on front wheel-drive cars propels the vehicle. They take a bit more abuse than the rear.
– MORAL: Nothing terrible will happen, except you will be forced to buy tires sooner.

WHEEL ALIGNMENT
– This is the MOST overlooked contributor to tire wear
– Alignment has absolutely nothing to do with the tires themselves, but will 100% adversely effect how your tires wear.
– Wheel alignment is referring to your suspension angles (Toe, Camber, Caster). All of these angles have a different effect on your tires’ wear. Most of the time resulting in wear only on the outer edge of your tires, feathering (choppy tires) or the vehicle will pull one way when your hands are off the steering wheel.
-MORAL: Get a wheel alignment done at least once a year, or if you are having any of these symptoms.

BALANCING

– While balancing will never be safety issue it is incredible annoying, usually causing a vibration around 60-70mph felt either in your steering wheel or the seat of your pants, while the brakes are NOT applied. Not to be confused with a brake pulsation which is a vibration when the brakes ARE applied.
– The reason for balancing tires is that no tire is perfectly round, nor is any rim. So weights are applied to offset these imperfections, providing a smoother ride.
– MORAL: Balance your tires when replacing them, or when symptoms are present.
– Treadwear/dry rot
– Most tires come with 10/32nds of an inch of tread, allowing your tires to maintain contact with the road surface, as well as evacuate water, snow, and road debris, from the tread patch via “sipes” and water veins. Tires should be replaced between 2-4/32nd’s of an inch. (You can get a tread depth gauge at an auto parts store, they are like $2.00. Or if you don’t have $2.00 you can use a penny.)

Treadwear is normal and will vary depending on driving type, tire maintenance, as well as the rubber compound for that particular tire. General rule of the thumb, the softer the rubber (lower treadwear rating) the better traction you get. The harder the rubber (higher treadwear rating) the longer a tire will last. Which leads me to my next point… dry rot.

. . . AND SPLIT SIDEWALL . . .

Often seen on vehicle that sit for long periods of time, or aren’t driven, dry rot occurs when the natural oils in the tire dry out and the rubber on the side wall begins to crack or separate. Every tire regardless of tread life is recommended to be replaced after 4 years by the Department of Transportation (Pssshhhh what do those guys know?) Don’t know how old your tires are? Every tire comes with a DOT number on the sidewall of the tire, which signifies what week of what year the
tire was made. The tires below was made in the third week of 2004 (very old).

Dry rot could result in the steel belts that hold your tires together, breaking apart, which will lead to a slow leak or a blow out. This belt separation will often look like your tires have been slashed, but trust me that’s not the case. (FYI: when a tire is slashed, it will be a clean cut, with no jagged edges and not as easily detectable as you might think.)

MORAL: Check your tread depth at every oil change, and inspect your tires DOT date to ensure you are not driving around on borrowed time.

I know this seems like an awful lot of information about tires, but again they are the only thing keeping you connected to the road. So with all of this in mind, remember to always check your tires, always take preventative actions to extend the life of your tires, and ALWAYS changes tires when they are needed, even if they are not worn out.

The safety of your vehicle is your responsibility, and if you fail to take care of your car, you are not only putting your life in danger, but the other drivers you share the road with, as well the AAA tow truck drivers, and the police officers that have to come to your aid on the side of the highway. Tires don’t give a shit if you’re black, white, famous, have a big nose, or how many followers you have on social media—they WILL blow up whenever they damn well please. And it will be 100% your fault since it is usually something that you could’ve prevented.